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From: Ingo Molnar <mingo@elte.hu>
To: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org,
	wfg@mail.ustc.edu.cn, levon@movementarian.org
Subject: Re: [PATCH] Make RCU task_struct safe for oprofile
Date: Sun, 27 Nov 2005 13:28:14 +0100	[thread overview]
Message-ID: <20051127122814.GA22692@elte.hu> (raw)
In-Reply-To: <20051126210726.GA5277@us.ibm.com>


* Paul E. McKenney <paulmck@us.ibm.com> wrote:

> Hello!
> 
> Applying RCU to the task structure broke oprofile, because 
> free_task_notify() can now be called from softirq.  This means that 
> the task_mortuary lock must be acquired with irq disabled in order to 
> avoid intermittent self-deadlock.  Since irq is now disabled, the 
> critical section within process_task_mortuary() has been restructured 
> to be O(1) in order to maximize scalability and minimize realtime 
> latency degradation.
> 
> Kudos to Wu Fengguang for finding this problem!

thanks, i applied this to the -rt tree.

	Ingo

      reply	other threads:[~2005-11-27 12:28 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-11-26 21:07 [PATCH] Make RCU task_struct safe for oprofile Paul E. McKenney
2005-11-27 12:28 ` Ingo Molnar [this message]

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